Self-organized quantum dots of diluted magnetic semiconductors Cd1-xMnxTe

Magneto-optical studies on self-organized quantum dots (QDs) of Cd1-xMnxTe were reported. Cd1-xMnxTe QDs with Mn composition less than 10% were grown successfully on the ZnTe(100) surface by atomic layer epitaxy. A typical dot size of 20 nm in diameter and 2 nm in height and density of the order of 10(11)cm(-2) were confirmed by atomic force microscope (AFM) measurement. In photoluminescence (PL) measurements on capped QDs, the excitonic emission from Cd1-xMnxTe dots was observed but the spectra were composed of two lines with a separation of 20-26 meV at low temperatures. In the dependence on the temperature, the excitation intensity and the magnetic field, the PL line at the lower-energy side exhibited peculiar behaviors, compared to that in the higher-energy side - rapid quenching with an increase of temperature up to 20 K, much smaller Zeeman shift under magnetic fields, and the saturation of the circular polarization at low magnetic fields. These features of the lower-energy line were discussed in relation to the excitonic magnetic polaron in QDs. Preliminary results of time-resolved PL and spatial-resolved PL using the far-field microscope are also shown. (C) 2000 Elsevier Science B.V. All rights reserved.